Removing focuser from Vixen SD81S for travel.

[CanesVenatici]

Hi all,

I am thinking of buying a Vixen SD81S as part of my portable set-up, and it would help a lot of the tube could be shortened for travel by removing the focuser assembly. I know that this often requires a bit of heat and strength, but my question is, if I did this would the baffle tube remain well out of harm's way inside the main tube, or would it protrude out of the main tube section? I understand that the baffle tube has been modified in the newer SD81 and have read that it now extends into the focuser, but I don't know how far it extends.  Has anyone removed the focuser and can give a definite answer?

Thanks!

[pete_gamby]

This diagram shows the ED81S and as you can see even on that model, the focusser extends well into the main tube. The attachment point of focusser to main tube is the far left vertical red line at the top of the diagram.

Actually, removing the focusser is quite easy - they unscrew without much force required. However, in my experience there is a risk of small flakes of the blackening paint coming off as you unscrew the tube so you need to take care not to have these drop on to the optics. Removing the focusser from the bottom while someone else holds the whole scope vertically seemed to minimise the risk.

There's also the chance that you might mis-thread the focusser when re-attaching it as the thread itself is very shallow. Take care to mark the release point (and the seated alignment position before removal).

Cheers, Pete

Edited May 27, 2021 by pete_gamby
Correcting model name to ED81S

[CanesVenatici]

Hi Pete,

Thanks for the tips. Removing the focuser doesn't seem to be too problematical, and I would only need to do this occasionally.

The real problem now is finding one. Here in Europe they seem to be out of stock everywhere , with no real indication as when the next shipment might arrive.